The Complementary Effects of Dabigatran Etexilate and Exercise Training on the Development and Stability of the Atherosclerotic Lesions in Diabetic ApoE Knockout Mice.

Aim: To determine the complementary effects of dabigatran etexilate (DE), exercise training (ET), and combination (DE + ET) on the development and stability of the atherosclerotic lesions in diabetic apoE knockout (apoE-/-) mice. Methods: In 48 male apoE-/- diabetic mice, streptozotocin (STZ) was induced for 5 consecutive days. Mice received a high-fat diet (HFD) for 8 weeks and then were randomized into four groups (1. Control/CG, 2. DEG: HFD with DE, 3. ETG: ET on treadmill, 4. DE + ETG: combination DE and ET treatment). At the end of the eighth week, all mice were euthanatized and morphometry of the aortic lesions at the level of aortic valve was obtained. Collagen, elastin, MCP-1, TNF-a, matrix metalloproteinases (MMP-2,-3,-9), and TIMP-1 concentrations within plaques at the aortic valve were determined. Results: All active groups had significantly smaller aorta stenosis (DEG:7.9 ± 2.2%, ETG:17.3 ± 5.3%, DE + ETG:7.1 ± 2.7%) compared to CG (23.3 ± 5.5% p < 0.05), reduced the relative intra-plaque content of MCP-1, macrophages, MMP-3, and MMP-9, and considerably increased collagen, elastin, and TIMP-1 (p < 0.05). Group 4 showed the most pronounced results (p < 0.05). Both DEG and DE + ETG significantly reduced MMP-2 and TNF-a concentrations compared to ETG and CG (p < 0.010). Conclusion: DE and ET treatment of diabetic apoE-/- mice resulted in complementary amelioration of atherosclerotic lesions development and stability, mediated by the anti-inflammatory modulation of both DE and ET.

How to Use Statins in Secondary Prevention of Atherosclerotic Diseases: from the Beneficial Early Initiation to the Potentially Unfavorable Discontinuation.

Statins, a class of lipid-lowering drugs, reduce morbidity and mortality in patients with established atherosclerosis-related cardiovascular disease. Early initiation of statin therapy after admission for acute coronary syndromes (ACS), stroke, or transient ischemic attack (TIA) is associated with improved cardiovascular outcomes. Moreover, high-dose statin treatment prior to coronary or carotid revascularization has been shown to reduce cardiovascular events in these patients. However, many patients may be undertreated, and a residual cardiovascular risk remains in current clinical practice. Despite the beneficial role of statins, their discontinuation rate among patients is still elevated leading to severe adverse cardiovascular events due to atherosclerotic plaque destabilization. In this review, we summarized the impact of statin treatment among patients, focusing on the initiation time-points as well as the potential harm derived by their discontinuation.

Exercise training inhibits atherosclerosis progression and reduces VE-cadherin levels within atherosclerotic plaques in hypercholesterolemic mice.

Vascular endothelial-cadherin (VE-cadherin), matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) have emerged as key-factors of atherogenesis. The aim of this study was to evaluate the effects of exercise training (ET) on those key-factors in relation to the progression of atherosclerotic lesions in hypercholesterolemic mice. Thirty male, apoE knockout (apoE-/-) mice were randomly assigned to the following equivalent groups: 1) CO-control: High-fat diet (HFD) administration for 12 weeks. 2) EX-exercise: HFD administration as in CO, and during the last 4 weeks (9th -12th week) ET on treadmill (5sessions/week, 60min/session). At the end of study, blood samples were obtained and all mice were sacrificed. Aortic roots were excised and analysed regarding the percentage of aortic stenosis, and the relative concentrations of collagen, elastin, VE-cadherin, MMP-8,-9 and TIMP-1,-2 within the atherosclerotic lesions. Aortic stenosis was significantly lower in the EX than the CO group (39.63 ± 7.22% vs 62.04 ± 8.55%; p < 0.001), along with considerable increase in fibrous cap thickness and of collagen and elastin contents within plaques (p < 0.05). Compared to controls, exercised-treated mice showed reduced intra-plaque relative concentrations of VE-cadherin (15.09 ± 1.89% vs 23.49 ± 3.01%, p < 0.001), MMP-8 (8.51 ± 2.24% vs 18.51 ± 4.08%, p < 0.001) and MMP-9 (12.1 ± 4.86% vs 18.88 ± 6.23%, p < 0.001). Inversely, the relative concentrations of TIMP-1 and TIMP-2 in the ET group were considerably higher by 62.5% and 31.2% than in the EX group (p < 0.05), respectively. Finally, body weight and lipids concentrations did not differ between groups at the end of the study (p > 0.05). ET treatment induced regression of established atherosclerotic lesions in apoE-/- mice and improved their stability. Those effects seemed to be mediated by favourable modification of VE-cadherin, MMPs and TIMPs.

Carotid Stent Restenosis and Thrombosis in Rabbits: The Effect of Antiplatelet Agents.

BACKGROUND: The purpose of the study was the comparative assessment of ticagrelor and clopidogrel effects on carotid post-balloon injury (PBI) and on post carotid artery stenting (CAS) rate of in-stent restenosis (ISR) and in-stent thrombosis in atherosclerotic rabbits. METHODS: Forty-eight New Zealand white rabbits on high-fat diet were randomized into 4 groups: A1: PBI and clopidogrel (30 mg/kg/d), A2: PBI and ticagrelor (21 mg/kg twice daily), B1: PBI, CAS, and clopidogrel (30 mg/kg/d), B2: PBI, CAS, and ticagrelor (21 mg/kg twice daily). All rabbits received orally aspirin (10 mg/kg/d) and interventions were performed in their right carotid arteries (RCAs). Optical coherence tomography (OCT) and carotid angiography were performed at end point, while platelet aggregation and lipid profile were measured. After euthanasia both carotids were obtained for histological examination. RESULTS: In B1 group, 3 rabbits presented thrombotic total occlusion of the stents, while none such episode was observed in B2 group. The neointimal areas in RCAs, calculated by OCT, did not differ between A1 and A2 groups, and between B1 and B2 groups (P > .05). From the histological findings, the intima/(media + intima) percentage (%) in RCAs of balloon-injured rabbits did not present any difference between groups (P = .812). Similarly, the immunohistochemically determined accumulation of endothelial cells and macrophages on vascular walls was equivalent between groups (P > .05). CONCLUSION: Following carotid balloon injury and stenting, clopidogrel and ticagrelor did not show any differential effects on the extent of neointimal formation and ISR in atherosclerotic rabbits receiving aspirin. Three thrombotic stent occlusions were noted in the clopidogrel treatment group, but this finding was not statistically significant.

Cilostazol Mediates Immune Responses and Affects Angiogenesis During the Acute Phase of Hind Limb Ischemia in a Mouse Model.

BACKGROUND: Cilostazol is a drug of choice for the treatment of intermittent claudication that also affects innate and adaptive immune cells. The purpose of our study was the evaluation of cilostazol's impact on the immune and angiogenic response in murine models of hind limb ischemia. METHODS: We used 108 immunodeficient NOD.CB17-Prkdcscid/J mice and 108 wild-type CB17 mice. At day 0 (D0), all animals underwent hind limb ischemia. Half of them in both groups received daily cilostazol starting at D0 and for the next 7 postoperative days, while the rest of them served as controls, receiving vehicle. Interleukin (IL) 2, IL-4, IL-6, IL-10, IL-17A, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) serum concentrations were measured by flow cytometry on postsurgery days D1, D3, D5, and D7. On D7, both groups underwent positron emission tomography scan with 68Ga-RGD. Mice were euthanatized and gastrocnemius muscles were obtained for histological evaluation. RESULTS: There was a statistically significant augmentation (P < .05) in IL-4, IL-10, IL-6, and IFN-γ concentrations in treated CB17 animals, while IL-2 was significantly suppressed. Significant difference was detected between the CiBisch and Bisch groups on D1 and D7 (P < .05) in CD31 staining. In treated NOD.CB17 animals, TNF-α, IL-6, and IFN-γ presented significant augmentation, while 68Ga-NODAGA-RGDfK uptake and CD31 expression were found significantly lower for both legs in comparison to the control. CONCLUSION: Cilostazol seems to significantly increase angiogenesis in wild-type animals during the first postoperational week. It also influences immune cells, altering the type of immune response by promoting anti-inflammatory cytokine production in wild-type animals, while it helps toward inflammation regression in immunodeficient animals.

Beneficial Effect of U-74389 G and Sildenafil in An Experimental Model of Flap Ischemia/Reperfusion Injury in Swine. Histological and Biochemical Evaluation of the Model.

Purpose of the study: Tissue reconstruction after burns, tumor excisions, infections or injuries is a frequent surgical challenge to avoid Ischemia-reperfusion injury. Lazaroids and sildenafil, through their mechanisms of action, have been studied for their protective effects on various organs subjected to IRI. In this study, we aimed to evaluate the therapeutic potential of U-74389G and sildenafil in a swine model of ischemia and reperfusion injury of latissimus dorsi flap. Materials and methods: Forty-two Landrace male pigs, weighing 28-35 kg, were equally (n = 6) randomized into the following groups: (a) Group I: control, (b) Group II: administration of U-74389G after ischemia, (c) Group III: administration of sildenafil after ischemia, (d) Group IV: administration of U-74389G and sildenafil after ischemia, (e) Group V: administration of U-74389G prior to ischemia, (f) Group VI: administration of sildenafil prior to ischemia, and (g) Group VII: administration of U-74389G and sildenafil prior to ischemia. Blood and tissue sampling was conducted before ischemia, 15 and 30 min after occlusion, 30, 60, 90, and 120 min after reperfusion. Results: Statistically significant reduction (p < 0.05) was detected in lymphocytes and polymorphonuclear leukocytes concentrations as well as in the appearance of edema after histopathologic evaluation of the ischemic tissue, especially in the groups of combined treatment. Measurements of malondialdeyde and tumour necrosis factor alpha in tissues revealed a significant decrease (p < 0.001) of these markers in the treatment groups when compared to the control, particularly in the latest estimated timepoints. Conclusions: The synergistic action of U-74389G and sildenafil seems protective and promising in cases of flap IRI during tissue reconstruction surgery.

Statins' Withdrawal Induces Atherosclerotic Plaque Destabilization in Animal Model-A "Rebound" Stimulation of Inflammation.

BACKGROUND: To evaluate the impact of atorvastatin discontinuation on the progression and stability of atherosclerotic plaques in a valid animal model of atherosclerosis. METHODS: Seventy ApoE-/- male mice fed with high-fat diet were randomly assigned into: (1) long-term intervention groups: (i) ATL, received atorvastatin for 12 weeks, (ii) CO-12W, control received vehicle for 12 weeks, (iii) ATW-6W, received atorvastatin for 6 weeks which was withdrawn for another 6 weeks. (2) Short-term intervention groups: (i) ATS received atorvastatin for 6 weeks, (ii) CO-6W, control receiving vehicle for 6 weeks, (iii) ATW-3D, ATW-7D, received atorvastatin for 6 weeks which was withdrawn for 3 days and 7 days, respectively. Daily dosage of atorvastatin was 20 mg/kg. Mice were killed and aortic samples were obtained for histological evaluation. RESULTS: Long-term atorvastatin treatment (ATL) induced atherosclerosis regression and stabilization compared to control ( P < .05). Atorvastatin's withdrawal was associated with acute (ATW-3D) reduction in connective tissue and collagen contents within plaques compared to ATS ( P < .05). Those changes were almost restored after a while (ATW-7D) and started appearing again after longer cessation (ATW-6W). Moreover, atorvastatin withdrawal induced shortly (ATW-3D) a peak in inflammatory markers (macrophages, MCP-1, tumor necrosis factor-α) and matrix metalloproteinases (MMP-3, MMP-9) concentrations within plaques, which sustained but to a lesser extent along time (ATW-7D, ATW-6W). CONCLUSION: Short-term withdrawal of atorvastatin seems to compromise its antiatherosclerotic effects, leading to an unstable phenotype of the atherosclerotic lesions and a rebound increase in inflammatory mediators. The clinical relevance of our findings requires further investigation.

Assessing the exploratory and anxiety-related behaviors of mice. Do different caging systems affect the outcome of behavioral tests?

Ample studies have shown that housing can affect the health, welfare and behavior of mice and therefore, the outcomes of certain experiments. The aim of this study was to investigate if three widely used housing systems, Open Top Cages (OTC), Motor Free Ventilated Cages (MFVC) and Individually Ventilated Cages (IVC) may affect exploratory and anxiety-related behaviors in mice. Subjects were 8week-old male C57Bl/6J mice (n=36) divided into three groups, OTC, IVC and MFVC groups, respectively. The experimental procedure consisted of two behavioral tests: the open field and the elevated plus maze test. Although there were no differences in the open field test, the results from the elevated plus maze showed that animals housed in the MFVCs exhibited increased exploratory and less anxiety-like behavior. It is concluded that the different caging systems may have an impact on the outcome of behavioral tests used to assess exploratory and anxiety like behavior in mice. Therefore, it is essential to take into consideration housing conditions when reporting, analyzing, and/or systematically reviewing the results of behavioral testing in mice.

Use of real-time ultrasonography as an alternative method for early detection, confirmation and evaluation of rat pregnancy.

Researchers sometimes face difficulties in the diagnosis of pregnancy and assessment of embryonic development. Ultrasonography (US) is a non-invasive imaging method with minimal side effects on the subjects or operators. It provides real-time evaluation of the physiology of rapidly moving structures (i.e., heart) and facilitates evaluation of fetal tissue development. US discerns tissues based on composition, making it the imaging method of choice for abdominal examination. In this study we used real-time US as an alternative method for early diagnosis of pregnancy in rats. Sixty-four Wistar rats aged 16-20 wk were examined, and day 8 was the earliest point at which pregnancy could be detected. We constructed a detailed timeline of embryonic features detectable by US on days 8 to 19. We trust this index will be a valuable tool. More refined work toward a more detailed "atlas" will help to reduce animal sacrifice during embryonic development studies.